Galls caused by the fungus Polycystis 

 pompholygodes L^v. 



on 



the leaf-stalks and leaves of Ranunculus repens Linn. 



PLATE 99. 

 Synonymy of Fungus. 



Urocystis pompholygodes L^v. 

 Popular Names of the Fungus. 



The Butteraip-snmt Cooke. 



TJie Crowfoot-smut Cooke. 

 Habitat of the Creeping Ranunculus.— This plant 



(often mistaken for the true buttercup) is, however, equally 



as plentiful in waste places, roadsides, meadows, and wet 



places all over Britain. 

 The Gall is formed by the rapid and enormous multi- 

 plication of the spores of the fungus within the tissues 



of the plant. 

 Position. — On the leaf-stalk and the leaf-segments. 

 Manner of Growth. — Singly or gregarious ; separate or 



coalesced. 

 Colour. — Pale green, reddish ; after the cuticle has ruptured, 



fuliginous. 

 Average Dimensions of a Mature Specimen. 



Length, 25 mm.; breadth, 10 mm.; girth, 15 mm. 

 May be sought during the months of April to December. 

 The Growth is complete by the end of September. 



A favourite situation for Ranunculus rcficns is by the side 

 of a country road or lane where the ground is very moist, or a 

 little stream of water is running, and the foliage above protects 

 the plant more or less from the sun. Such conditions are very 

 favourable for the growth of the fungus, where at times it 

 flourishes most vigorously, and it is remarkable how little the 

 vigour of the plant is affected by it. 



The gall is also figured by M. C. Cooke, " Rust, Smut, 

 Mildew, and Mould," plate 9. 



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